If they were hired by Amex, then they ARE a debt collection agency, and must abide by Title 8 law
Now that you are being sued, I HIGHLY recommend that you get an attorney to represent you.
Alternatively, you could offer a settlement (try 40%) and see if that will make them happy and drop the suit.
As for the dates, make sure that the court knows that you are scheduled for jury duty on the date of the pretrial. They'll either relieve you of the jury duty or move the pretrial... that would be up to the court.